A panel assembly that includes at least a first upper base layer made of a thermoplastic material that includes fibers therein, at least a first lower base layer made of a thermoplastic material that includes fibers therein, and at least a first reinforcement layer sandwiched or positioned between the first upper base layer and first lower base layer. The upper and lower surfaces of the first reinforcement layer have a smaller surface area than the upper and lower surfaces of the first upper and first lower base layers. The lower surface of the first upper base layer is welded to the upper surface of the first reinforcement layer, and the lower surface of the first reinforcement layer is welded to the upper surface of the first lower base layer.